The Right It
This is "the bible" of pretotyping. The first full-length book by Alberto Savoia.
Packed with examples on how to pretotype every type of product, service, or idea, reading The Right It is like having a personal six hour lesson on pretotyping tools, techniques, and tactics by Alberto Savoia.
Pretotyping @ Stanford
If you only have 30 minutes and want a quick introduction to why and how to pretotype, this video of one of Alberto's seminars at Stanford is a great starting point.
Quick Reference: Pretotyping Techniques (from Stanford)
Download this one-page pretotyping reference I created for the MS&E 277 course at Stanford.